selftests/zram01.sh: Fix compression ratio calculation
authorYang Xu <xuyang2018.jy@fujitsu.com>
Thu, 27 Jan 2022 09:11:36 +0000 (17:11 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 23 Feb 2022 10:56:39 +0000 (11:56 +0100)
commit75fc3ca360c2959e7b23fa4acdc0809f41770c90
treec319ffb0f6d520b0bcc3d0363bf58728306fea19
parent70e0d201013b894c4f5d3744539f0883ab2aeca9
selftests/zram01.sh: Fix compression ratio calculation

[ Upstream commit d18da7ec3719559d6e74937266d0416e6c7e0b31 ]

zram01 uses `free -m` to measure zram memory usage. The results are no
sense because they are polluted by all running processes on the system.

We Should only calculate the free memory delta for the current process.
So use the third field of /sys/block/zram<id>/mm_stat to measure memory
usage instead. The file is available since kernel 4.1.

orig_data_size(first): uncompressed size of data stored in this disk.
compr_data_size(second): compressed size of data stored in this disk
mem_used_total(third): the amount of memory allocated for this disk

Also remove useless zram cleanup call in zram_fill_fs and so we don't
need to cleanup zram twice if fails.

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tools/testing/selftests/zram/zram01.sh